Is there a line render engine for Blender?
Blender Internal
BI can render wireframes on edge only meshes, whether shaded or shadeless:

BI can also render halos, which work on vertex only meshes (there are a few in the middle of the above scene), but they are affected by distance.
OpenGL
However, you could try using the openGL preview render (using the same system that renders the viewport)
Unfortunately, options for coloring objects individually is rather limited using meshes without faces. You can tweak some things (e.g. vertex size) by editing the themes, but this is obviously not what it was designed for.
You can render animations and stills with openGL render by clicking the buttons in the header of the 3D view, or in the render menu in the Info panel (at the top of the window):

For example:

Original answer:

Freestyle can render a scene as svg, using either SVGwriter or this set of python scripts.
Note that freestyle requires faces to work.